Hvac controller with a temperature sensor mounted on a flex circuit

ABSTRACT

A Heating, Ventilation, and Air Conditioning (HVAC) controller may include a housing, a display, a printed wiring board, a flextail, and a temperature sensor. The housing may be configured to house the display, the printed wiring board, the flextail, and the temperature sensor. The flextail may extend from, for example, the display or other component of the HVAC controller, along the interior surface of the housing, and connect to a connector on the printed wiring board. The temperature sensor may be mounted on the flextail, and connected to the printed circuit board via the flex tail or other connection. In some cases, the temperature sensor may be positioned on the flextail such that when the flextail is connected to the printed wiring board, the temperature sensor is positioned adjacent a lower part of the housing, where less internal heat generated by the internal electrical components of the HVAC controller will reside.

PRIORITY

This application claims the benefit of U.S. Provisional Application Ser.No. 62/380,219, filed Aug. 26, 2016, the entirety of which isincorporated herein by reference.

TECHNICAL FIELD

The present disclosure pertains to Heating, Ventilation, and/or AirConditioning (HVAC) systems. More particularly, the present disclosurepertains to HVAC controllers, such as thermostats.

BACKGROUND

Heating, Ventilation, and/or Air Conditioning (HVAC) systems are oftenused to control the comfort level within a building or other structure.Such HVAC systems typically include an HVAC controller that controlsvarious HVAC components of the HVAC system in order to affect and/orcontrol one or more environmental conditions within the building. Inmany cases, the HVAC controller is mounted to an internal wall of thebuilding and provides control signals to various HVAC components of theHVAC system, sometimes via a number of control wires that extend throughthe wall. Improvements in the hardware, user experience, andfunctionality of such HVAC controllers would be desirable.

SUMMARY

The present disclosure pertains generally to an HVAC controller with atemperature sensor. In some cases, the HVAC controller may be athermostat. An HVAC controller may include a housing, a display, aprinted wiring board, a flextail, and a temperature sensor such as athermistor. The housing of the HVAC controller may be configured tohouse the display, the printed wiring board, the flextail, and thetemperature sensor. The flextail may be a flexible circuit, a ribboncable or any other suitable fixable circuit. The flextail may extendfrom, for example, the display or other component of the HVACcontroller, along the interior surface of the housing, and connect to aconnector on the printed wiring board. The temperature sensor may bemounted on the flextail and connected to the printed circuit board viathe flex tail or other connection. In some cases, the temperature sensormay be positioned on the flextail such that when the flextail isconnected to the printed wiring board, the temperature sensor ispositioned adjacent a lower part of the housing, where less internalheat generated by the internal electrical components of the HVACcontroller will reside.

The preceding summary is provided to facilitate an understanding of someof the features of the present disclosure and is not intended to be afull description. A full appreciation of the disclosure can be gained bytaking the entire specification, claims, drawings, and abstract as awhole.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more completely understood in consideration of thefollowing description of various illustrative embodiments of thedisclosure in connection with the accompanying drawings, in which:

FIG. 1 is a schematic view of an illustrative HVAC system servicing abuilding or structure;

FIG. 2 is a schematic view of an illustrative HVAC control system thatmay facilitate access and/or control of the HVAC system of FIG. 1;

FIG. 3 is a schematic perspective view of an illustrative thermostatassembly that may be used in the HVAC control system of FIG. 2;

FIG. 4 is a schematic exploded perspective view of the illustrativethermostat assembly of FIG. 3;

FIG. 5 is a schematic front perspective view of an illustrativethermostat;

FIG. 6 is a schematic back perspective view of the illustrativethermostat of FIG. 5;

FIG. 7 is a schematic exploded front perspective view of theillustrative thermostat of FIG. 5;

FIG. 8 is a schematic exploded back perspective view of the illustrativethermostat of FIG. 5;

FIG. 9 is a schematic interior-side view of an illustrative front coverof a thermostat;

FIG. 10 is a schematic interior-side view of an illustrative back coverof a thermostat;

FIG. 11 is a schematic side view of the illustrative back cover of FIG.10;

FIG. 12 is a cross-sectional view showing an illustrative latch latchedwith an illustrative latch receiver;

FIG. 13 is a cross-sectional view showing an illustrative first guidefeature engaging an illustrative second guide feature;

FIG. 14 is a schematic perspective view of an illustrative display of athermostat; and

FIG. 15 is a schematic interior side view of illustrative components ofa thermostat.

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit aspects of thedisclosure to the particular illustrative embodiments described. On thecontrary, the intention is to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the disclosure.

DESCRIPTION

The following description should be read with reference to the drawingswherein like reference numerals indicate like elements. The drawings,which are not necessarily to scale, are not intended to limit the scopeof the disclosure. In some of the figures, elements not believednecessary to an understanding of relationships among illustratedcomponents may have been omitted for clarity.

All numbers are herein assumed to be modified by the term “about”,unless the content clearly dictates otherwise. The recitation ofnumerical ranges by endpoints includes all numbers subsumed within thatrange (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include the plural referents unless thecontent clearly dictates otherwise. As used in this specification andthe appended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise.

It is noted that references in the specification to “an embodiment”,“some embodiments”, “other embodiments”, etc., indicate that theembodiment described may include a particular feature, structure, orcharacteristic, but every embodiment may not necessarily include theparticular feature, structure, or characteristic. Moreover, such phrasesare not necessarily referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with an embodiment, it is contemplated that the feature,structure, or characteristic may be applied to other embodiments whetheror not explicitly described unless clearly stated to the contrary.

The present disclosure is directed generally at building automationsystems. Building automation systems are systems that control one ormore operations of a building. Building automation systems can includeHVAC systems, security systems, fire suppression systems, energymanagement systems and other systems. While HVAC systems with HVACcontrollers are used as an example below, it should be recognized thatthe concepts disclosed herein can be applied to building automationsystems more generally.

FIG. 1 is a schematic view of a building 2 having an illustrativeheating, ventilation, and air conditioning (HVAC) system 4. While FIG. 1shows a typical forced air type HVAC system, other types of HVAC systemsare contemplated including, but not limited to, boiler systems, radiantheating systems, electric heating systems, cooling systems, heat pumpsystems, and/or any other suitable type of HVAC system, as desired. Theillustrative HVAC system 4 of FIG. 1 includes one or more HVACcomponents 6, a system of ductwork and air vents including a supply airduct 10 and a return air duct 14, and one or more HVAC controllers 18.The one or more HVAC components 6 may include, but are not limited to, afurnace, a heat pump, an electric heat pump, a geothermal heat pump, anelectric heating unit, an air conditioning unit, a humidifier, adehumidifier, an air exchanger, an air cleaner, a damper, a valve,and/or the like.

It is contemplated that the HVAC controller(s) 18 may be configured tocontrol the comfort level in the building or structure by activating anddeactivating the HVAC component(s) 6 in a controlled manner. The HVACcontroller(s) 18 may be configured to control the HVAC component(s) 6via a wired or wireless communication link 20. In some cases, the HVACcontroller(s) 18 may be a thermostat, such as, for example, a wallmountable thermostat, but this is not required in all embodiments. Sucha thermostat may include (e.g. within the thermostat housing orelsewhere) or have access to one or more temperature sensor(s) (e.g.,one or more thermistors or other temperature sensors) for sensingambient temperature at or near the thermostat. In some instances, theHVAC controller(s) 18 may be a zone controller, or may include multiplezone controllers each monitoring and/or controlling the comfort levelwithin a particular zone in the building or other structure.

In the illustrative HVAC system 4 shown in FIG. 1, the HVAC component(s)6 may provide heated air (and/or cooled air) via the ductwork throughoutthe building 2. As illustrated, the HVAC component(s) 6 may be in fluidcommunication with every room and/or zone in the building 2 via theductwork 10 and 14, but this is not required. In operation, when a heatcall signal is provided by the HVAC controller(s) 18, an HVAC component6 (e.g. forced warm air furnace) may be activated to supply heated airto one or more rooms and/or zones within the building 2 via supply airducts 10. The heated air may be forced through supply air duct 10 by ablower or fan 22. In this example, the cooler air from each zone may bereturned to the HVAC component 6 (e.g. forced warm air furnace) forheating via return air ducts 14. Similarly, when a cool call signal isprovided by the HVAC controller(s) 18, an HVAC component 6 (e.g. airconditioning unit) may be activated to supply cooled air to one or morerooms and/or zones within the building or other structure via supply airducts 10. The cooled air may be forced through supply air duct 10 by theblower or fan 22. In this example, the warmer air from each zone may bereturned to the HVAC component 6 (e.g. air conditioning unit) forcooling via return air ducts 14. In some cases, the HVAC system 4 mayinclude an internet gateway or other device 23 that may allow one ormore of the HVAC components 6, as described herein, to communicate overa wide area network (WAN) such as, for example, the Internet.

In some cases, the system of vents or ductwork 10 and/or 14 may includeone or more dampers 24 to regulate the flow of air, but this is notrequired. For example, one or more dampers 24 may be coupled to one ormore HVAC controller(s) 18, and can be coordinated with the operation ofone or more HVAC components 6. The one or more HVAC controller(s) 18 mayactuate dampers 24 to an open position, a closed position, and/or apartially open position to modulate the flow of air from the one or moreHVAC components to an appropriate room and/or zone in the building orother structure. The dampers 24 may be particularly useful in zoned HVACsystems, and may be used to control which zone(s) receives conditionedair from the HVAC component(s) 6.

In many instances, one or more air filters 30 may be used to remove dustand other pollutants from the air inside the building 2. In theillustrative example shown in FIG. 1, the air filter(s) 30 is installedin the return air duct 14, and may filter the air prior to the airentering the HVAC component 6, but it is contemplated that any othersuitable location for the air filter(s) 30 may be used. The presence ofthe air filter(s) 30 may not only improve the indoor air quality, butmay also protect the HVAC components 6 from dust and other particulatematter that would otherwise be permitted to enter the HVAC component 6.

In some cases, and as shown in FIG. 1, the illustrative HVAC system 4may include an equipment interface module (EIM) 34. When provided, theequipment interface module 34 may, in addition to controlling the HVACunder the direction of the thermostat, be configured to measure ordetect a change in a given parameter between the return air side and thedischarge air side of the HVAC system 4. For example, the equipmentinterface module 34 may measure a difference in temperature, flow rate,pressure, or a combination of any one of these parameters between thereturn air side and the discharge air side of the HVAC system 4. In somecases, the equipment interface module 34 may be adapted to measure thedifference or change in temperature (delta T) between a return air sideand discharge air side of the HVAC system 4 for the heating and/orcooling mode. The delta T for the heating and cooling modes may becalculated by subtracting the return air temperature from the dischargeair temperature (e.g. delta T=discharge air temperature−return airtemperature)

In some cases, the equipment interface module 34 may include a firsttemperature sensor 38 a located in the return (incoming) air duct 14,and a second temperature sensor 38 b located in the discharge (outgoingor supply) air duct 10. Alternatively, or in addition, the equipmentinterface module 34 may include a differential pressure sensor includinga first pressure tap 39 a located in the return (incoming) air duct 14,and a second pressure tap 39 b located downstream of the air filter 30to measure a change in a parameter related to the amount of flowrestriction through the air filter 30. In some cases, the equipmentinterface module 34, when provided, may include at least one flow sensorthat is capable of providing a measure that is related to the amount ofair flow restriction through the air filter 30. In some cases, theequipment interface module 34 may include an air filter monitor. Theseare just some examples.

When provided, the equipment interface module 34 may be configured tocommunicate with the HVAC controller 18 via, for example, a wired orwireless communication link 42. In other cases, the equipment interfacemodule 34 may be incorporated or combined with the HVAC controller 18.In some instances, the equipment interface module 34 may communicate,relay or otherwise transmit data regarding the selected parameter (e.g.temperature, pressure, flow rate, etc.) to the HVAC controller 18. Insome cases, the HVAC controller 18 may use the data from the equipmentinterface module 34 to evaluate the system's operation and/orperformance. For example, the HVAC controller 18 may compare datarelated to the difference in temperature (delta T) between the returnair side and the discharge air side of the HVAC system 4 to a previouslydetermined delta T limit stored in the HVAC controller 18 to determine acurrent operating performance of the HVAC system 4.

FIG. 2 is a schematic view of an illustrative HVAC control system 50that facilitates remote access and/or control of the illustrative HVACsystem 4 shown in FIG. 1. The HVAC control system 50 may be considered abuilding automation system or part of a building automation system. Theillustrative HVAC control system 50 includes an HVAC controller, as forexample, HVAC controller 18 (see FIG. 1) that is configured tocommunicate with and control one or more HVAC components 6 of the HVACsystem 4. As discussed above, the HVAC controller 18 may communicatewith the one or more HVAC components 6 of the HVAC system 4 via a wiredor wireless link 20. Additionally, the HVAC controller 18 maycommunicate over one or more wired or wireless networks that mayaccommodate remote access and/or control of the HVAC controller 18 viaanother device such as a smart phone, tablet, e-reader, laptop computer,personal computer, key fob, or the like. As shown in FIG. 2, the HVACcontroller 18 may include a first communications port 52 forcommunicating over a first network 54, and in some cases, a secondcommunications port 56 for communicating over a second network 58. Insome cases, the first network 54 may be a wireless local area network(LAN), and the second network 58 (when provided) may be a wide areanetwork or global network (WAN) including, for example, the Internet. Insome cases, the wireless local area network 54 may provide a wirelessaccess point and/or a network host device that is separate from the HVACcontroller 18. In other cases, the wireless local area network 54 mayprovide a wireless access point and/or a network host device that ispart of the HVAC controller 18. In some cases, the wireless local areanetwork 54 may include a local domain name server (DNS), but this is notrequired for all embodiments. In some cases, the wireless local areanetwork 54 may be an ad-hoc wireless network, but this is not required.

In some cases, the HVAC controller 18 may be programmed to communicateover the second network 58 with an external web service hosted by one ormore external web server(s) 66. A non-limiting example of such anexternal web service is Honeywell's TOTAL CONNECT™ web service. The HVACcontroller 18 may be configured to upload selected data via the secondnetwork 58 to the external web service where it may be collected andstored on the external web server 66. In some cases, the data may beindicative of the performance of the HVAC system 4. Additionally, theHVAC controller 18 may be configured to receive and/or download selecteddata, settings and/or services sometimes including software updates fromthe external web service over the second network 58. The data, settingsand/or services may be received automatically from the web service,downloaded periodically in accordance with a control algorithm, and/ordownloaded in response to a user request. In some cases, for example,the HVAC controller 18 may be configured to receive and/or download anHVAC operating schedule and operating parameter settings such as, forexample, temperature set points, humidity set points, start times, endtimes, schedules, window frost protection settings, and/or the like fromthe web server 66 over the second network 58. In some instances, theHVAC controller 18 may be configured to receive one or more userprofiles having at least one operational parameter setting that isselected by and reflective of a user's preferences. In still otherinstances, the HVAC controller 18 may be configured to receive and/ordownload firmware and/or hardware updates such as, for example, devicedrivers from the web server 66 over the second network 58. Additionally,the HVAC controller 18 may be configured to receive local weather data,weather alerts and/or warnings, major stock index ticker data, trafficdata, and/or news headlines over the second network 58. These are justsome examples.

Depending upon the application and/or where the HVAC user is located,remote access and/or control of the HVAC controller 18 may be providedover the first network 54 and/or the second network 58. A variety ofremote wireless devices 62 may be used to access and/or control the HVACcontroller 18 from a remote location (e.g. remote from the HVACController 18) over the first network 54 and/or second network 58including, but not limited to, mobile phones including smart phones,tablet computers, laptop or personal computers, wireless network-enabledkey fobs, e-readers, and/or the like. In many cases, the remote wirelessdevices 62 are configured to communicate wirelessly over the firstnetwork 54 and/or second network 58 with the HVAC controller 18 via oneor more wireless communication protocols including, but not limited to,cellular communication, ZigBee, REDLINK™, Bluetooth, WiFi, IrDA,dedicated short range communication (DSRC), EnOcean, and/or any othersuitable common or proprietary wireless protocol, as desired.

In some cases, an application program code (i.e. app) stored in thememory of the remote device 62 may be used to remotely access and/orcontrol the HVAC controller 18, but this is not required. Theapplication program code (app) may be downloaded from an external webservice, such as the web service hosted by the external web server 66(e.g. Honeywell's TOTAL CONNECT™ web service) or another external webservice (e.g. ITUNES® or Google Play). In some cases, the app mayprovide a remote user interface for interacting with the HVAC controller18 at the user's remote device 62. For example, through the userinterface provided by the app, a user may be able to change operatingparameter settings such as, for example, temperature set points,humidity set points, start times, end times, schedules, window frostprotection settings, accept software updates and/or the like.Communications may be routed from the user's remote device 62 to the webserver 66 and then, from the web server 66 to the HVAC controller 18. Insome cases, communications may flow in the opposite direction such as,for example, when a user interacts directly with the HVAC controller 18to change an operating parameter setting such as, for example, aschedule change or a set point change. The change made at the HVACcontroller 18 may be routed to the web server 66 and then from the webserver 66 to the remote device 62 where it may reflected by theapplication program executed by the remote device 62.

In some cases, a user may be able to interact with the HVAC controller18 via a user interface provided by one or more web pages served up bythe web server 66. The user may interact with the one or more web pagesusing a variety of internet capable devices to effect a setting or otherchange at the HVAC controller 18, and in some cases view usage data andenergy consumption data related to the usage of the HVAC system 4. Insome cases, communication may occur between the user's remote device 62and the HVAC controller 18 without being relayed through a server suchas external server 66. These are just some examples.

FIG. 3 is a perspective view of an illustrative thermostat assembly 80,and FIG. 4 is an exploded perspective view of the illustrativethermostat assembly 80 of FIG. 3. In some instances, the thermostatassembly 80 may be considered as an example of the HVAC controller 18referenced in FIGS. 1 and 2. In some instances, and with particularreference to FIG. 4, the thermostat assembly 80 may include a thermostat82 and a wall mountable connector 84. The wall mountable connector 84may be configured to accommodate field wires that enter from a rear ofthe wall mountable connector 84. When so provided, the wall mountableconnector 84 may provide an electrical connection between terminals ofthe thermostat 82 and field wires (not illustrated) of the HVAC system 4(FIGS. 1 and 2).

In the example shown, the wall mountable connector 84 may also provide amechanical connection to the thermostat 82 and thus may be used tosecure the thermostat 82 in place relative to a vertical surface such asa wall. The wall mountable connector 84 may be considered as being afully integrated connector, providing electrical and mechanicalconnections to the thermostat 82 in a compact design that is smallenough to be used with a variety of different thermostats and yetaffords the ability to easily connect a plurality of field wires to thewall mountable connector 84.

In some instances, the wall mountable connector 84 itself may be securedto an adapter plate 86 that is configured to be secured to an electricaljunction box or the like (not illustrated) disposed within the wall. Insome cases, the adapter plate 86 may not be used, particularly if thefield wires simply exit the wall through a hole in the wall. In somecases, an installer may utilize the adapter plate 86 if there is a largehole in the wall through which the field wires exit, even if there is nojunction box within the wall.

In some cases, a wall covering plate 88 may be included to provide anaesthetically pleasing appearance to the thermostat assembly 80. In someinstances, for example, the wall covering plate 88 may be larger thanthe thermostat 82 and may hide blemishes left on the wall from previousthermostat installations. In some cases, a homeowner may, for example,decide they want to install a wall covering plate 88 that has adifferent shape or design, or perhaps is a different color to match thecolor of a new thermostat.

FIG. 5 is a front perspective view of the thermostat 82. The thermostat82 may have a housing 90 having a front cover 92 and a back cover 93(not shown in FIG. 5). The front cover 92 may define an opening 94through which a display 96 may be viewed and through which a user mayinteract with a touch screen 98.

FIG. 6 is a back perspective view of the thermostat 82. As seen in FIG.6, the front cover 92 may engage the back cover 93 to form the housing90 of the thermostat. In some instances, one or more pins 100 mayextending through the back cover 93 to engage the wall mountableconnector 84. As discussed below, the front cover 92 and the back cover93 may be configured to reduce or prevent gaps along where edges of thefront cover 92 meet edges of the back cover 93.

FIGS. 7 and 8 are front and back, respectively, exploded perspectiveviews of the thermostat 82. The thermostat 82 may contain one or moreelectrical and/or non-electrical components that may interact with oneanother to form a robust thermostat. In the example seen in FIGS. 7 and8, the thermostat 82 may include a front cover 92 defining opening 94, atouch screen 98 having a screen flextail 108, a display 96 having adisplay flextail 110, a back light reflector and display spacer assembly104, control circuitry at least partially implemented by a printedwiring board (PWB) 102, a PWB spacer 106, and the back cover 93.

The display 96 and the touch screen 98 (e.g., an indium tin oxide (ITO)touch screen or other type of touch screen) may work together to form aninterface assembly 97 (e.g., a display assembly). A user may interactwith interface assembly 97 in any manner, including, but not limited to,touching the touch screen 98, through interacting with a remote device(not shown), and/or through one or more other interaction mechanisms.

In some instances, the interface assembly 97 may include a 2-dimensionalarray of pixels that covers the full display area of the display 96. Insome instances, the interface assembly 97 may include a display 96 thatis a segmented display, which may include a plurality of predefinedsegments that can be switched on and off to give the appearance ofdesired characters, icons or other graphical features. In a segmenteddisplay, the predefined segments may not be arranged in a full2-dimensional array of pixels that covers the full display area of thedisplay 96. Rather, at least some of the predefined segments may beelongated, define a symbol or icon, or otherwise do not fall into asimple 2-dimensional array of pixels.

It is contemplated that the display 96 may be any suitable display panelusing any suitable display panel technology. For example, the display 96may include the following types of display panels: Eidophor,Electroluminescent display (ELD), Electronic paper (E Ink, Gyricon),Light emitting diode display (LED), Cathode ray tube (CRT) (Monoscope),Liquid-crystal display (LCD) (TFT, LED, Blue Phase, IPS), Plasma displaypanel (PDP) (ALiS), Digital Light Processing (DLP), Liquid crystal onsilicon (LCoS), Organic light-emitting diode (OLED) (AMOLED), Organiclight-emitting transistor (OLET), Surface-conduction electron-emitterdisplay (SED), Field emission display (FED), Laser TV (Quantum dot,Liquid crystal), MEMS display (IMoD, TMOS, DMS), Quantum dot display(QD-LED), Ferro liquid display (FLD), Thick-film dielectricelectroluminescent technology (TDEL), Telescopic pixel display (TPD),Laser Phosphor Display (LPD), or other type of display panel.

The back light reflector and display spacer assembly 104 may comprise aframe 105, a backlight guide plate 107, a spacer 109 and/or one or moreother components. The components of the back light reflector and displayspacer assembly 104 may be made from any material. In one example, thecomponents of the back light reflector and display spacer assembly 104may be made from plastic, but this is not required. As seen in FIG. 7,the printed wiring board 102 may include one or more lights sources(e.g., light emitting diodes (LEDs) or other light sources) and the backlight reflector and display spacer assembly 104 may receive light fromthe light sources and deflect the light in a manner that may provideuniform or substantially uniform backlighting for the display 96.

In some cases, the back light reflector and display spacer assembly 104may act as a spacer or space filler between the interface assembly 97(e.g., the touch screen 98 and/or the display 96) and the PWB 102. Insuch situations and/or others, the back light reflector and displayspacer assembly 104 may receive the touch screen 98 and/or display 96 ata side facing the front cover 92. When the back light reflector anddisplay spacer assembly 104 and the touch screen 98 and/or display 96received therein are inserted into the front cover 92, the back lightreflector and display spacer assembly 104 may help ensure the touchscreen 98 and/or display 96 are properly aligned with respect to theopening 94 of the front cover 92.

As seen in FIGS. 7 and 8, the back cover 93 may have a tunnel 112. Thetunnel 112 may facilitate locating a pin leading to the PWB 102. Thetunnel 112 may be utilized at any time, but in one example, the tunnel112 may be used during programming and/or testing and may facilitatecorrect positioning of the PWB 102 against a testing fixture havingelectrical contacts.

During assembly of the thermostat 82, the various component parts may beassembled in a variety of ways. However, to ensure proper alignment ofthe various components of the thermostat 82, one example order mayinclude inserting the touch screen 98, the display 96, and the backlight reflector and display spacer assembly 104 into the front cover 92.When inserted in the front cover 92, the touch screen 98, the display96, and/or the back light reflector and display spacer assembly 104 maybe entirely or at least partially surrounded by ribs (e.g., rib features120 described below with respect to FIG. 9) of the front cover 92, wherethe ribs may act with the back light reflector and display spacerassembly 104 to align the touch screen 98 and/or the display 96 with theopening 94. The PWB 102 and PWB spacer 106 may then be placed over theback light reflector and display spacer assembly 104 and against theribs of the front cover 92, where a front side of the PWB 102 may befacing a back side of the back light reflector and display spacerassembly 104. The ribs of the front cover 92 may interact with the slotsand/or other features of the PWB 102 to properly position the PWB 102within the front cover 92. Then, the back cover 93 may be placed overthe PWB 102 and the PWB spacer 106. The back cover 93 may push againstthe back side of the PWB at one or more locations and may lock thecomponents of the thermostat 82 in their respective positions within thehousing 90. In some cases, the back cover 93 may latch or otherwiseengage the front cover 92, as discussed further below.

The housing 90 may have an interior side and an exterior side, where oneor more electrical components may be enclosed within the housing 90 onthe interior side. FIG. 9 is a view of an interior side of the frontcover 92. The front cover 92 may include one or more rib features 120configured to engage and/or otherwise align components of the thermostat82 within the front cover 92 and the back cover 93. For claritypurposes, only some of the depicted rib features 120 are labeled.

The front cover 92 may include one or more latches 122. The latches 122may be configured to engage latch receivers 132 (discussed with respectto FIGS. 10 and 12 below) as the front cover 92 and the back cover 93come into contact with one another. The latches 122 and the latchreceivers 132 may releasably secure the front cover 92 to the back cover93. In some instances, the latches 122 may extend inward from an inneredge 124 of the front cover 92.

There may be any number of latches 122 on the front cover 92. In someinstances, there may be one (1) latch, two (2) latches, three (3)latches, four (4) latches, six (6) latches, eight (8) latches or othernumber of latches 122.

The latches 122 may be equally spaced around a perimeter (e.g., the edge124 or other perimeter) of the front cover 92. Alternatively, one ormore of the latches 122 may be irregularly spaced around the perimeterof the front cover 92. As shown in the example depicted in FIG. 9, thefront cover 92 may include eight (8) latches 122. The eight (8) latchesof FIG. 9 include four pairs of latches, with each pair of latchesservicing one side of the front cover 92.

The front cover 92 may include one or more first guide features 126. Thefirst guide features 126 may be configured to engage associated secondguide features 134 (discussed further with respect to FIGS. 10 and 13below) prior to the latches 122 fully interacting with associated latchreceivers 132 as the front cover 92 and the back cover 93 are broughttogether.

The first guide features 126 may be configured to receive and/or engagesecond guide features 134 as the front cover 92 and the back cover 93come into contact with one another. In some instances, one or more ofthe first guide features 126 may be configured to be received within anassociated second guide features 134, but this is not required.

In one example of the first guide features 126, the first guide features126 may extend from an interior surface of the front cover 92 and forman encircled opening for receiving a second guide features 134, as bestshown in FIG. 13. In some cases, the first guide features 126 may be adome, a pin, or have a different configuration.

The front cover 92 may include any number of first guide features 126.In some instances, there may be one (1), two (2), three (3), four (4),six (6), eight (8) first guide features 126 or other number of firstguide features 126. As shown in FIG. 9, a first guide feature 126 may belocated midway between each pair of latches 122. In some cases, a firstguide feature 126 may be located in each corner as well. In some cases,the first guide features 126 located in the corners of the interior sideof the front cover 92 may take a different form than the first guidefeatures 126 along the side edges of the interior side of the frontcover 92.

When the housing is fully assembled, the first guide features 126 andthe second guide features 134 (discussed below) may facilitatemaintaining a desired shape of the housing 90 by providing supportbetween latches to reduce or prevent gaps from forming along locationswhere edges of the front cover 92 meet edges of the back cover 93. Insome cases, without the guide features, permanent gaps may form if thehousing sidewalls become deformed as a result of the latches fullyengaging the latch receivers.

FIG. 10 is a view of an interior side of the back cover 93 and FIG. 11is a side view of the back cover 93 of FIG. 10. In the example shown,the back cover 93 may include one or more latch receivers 132, pin holes138 (for clarity purposes, only some pin holes 138 are labeled)configured to receive pins extending from the PWB 102, and/or otherfeatures.

The latch receivers 132 may be configured to engage latches 122(discussed above with respect to FIG. 9) as the front cover 92 and theback cover 93 come into contact with one another. The latch receivers132 and the latches 122 may releasably secure the front cover 92 to theback cover 93. In some instances, and as best shown in FIG. 12, thelatch receivers 132 may form a latch slot 137 extending inward from aside edge 136 of the back cover 93, and may bend the latches 122, andthe sidewall of the front cover 92, outward until the latches 122 snapinto the latch slot 137. FIG. 12 is a cross-sectional view showing alatch 122 fully latched with a latch receiver 132.

In some cases, the second guide features 134 help to prevent the firstguide features 126, and thus the sidewall of the front cover 92, fromalso bending outward, as best shown in FIG. 13, thereby limiting orpreventing the sidewalls of the front cover 92 from becoming permanentlydeformed. FIG. 13 is a cross-sectional view showing a first guidefeature 126 engaging a second guide feature 134. In some cases, withoutthe guide features 126 and 134, permanent gaps may form if the sidewallsof the front cover 92 become deformed as a result of the latches 122fully engaging the latch receivers 132.

There may be any number of latch receivers 132 on the back cover 93. Insome instances, there may be one (1) latch receiver, two (2) latchreceivers, three (3) latch receivers, four (4) latch receivers, six (6)latch receivers, eight (8) latch receivers, or other number of latchreceiver 132. In one example, there may be the same number of latchreceivers 132 as there are latches 122. As shown in FIG. 10, the backcover 93 may include eight (8) latch receivers 132 and the latchreceivers 132 may be aligned with the latches 122 of the front cover 92.

As shown, the back cover 93 may include one or more second guidefeatures 134. The second guide features 134 may be configured to beinserted into and/or engage the first guide features 126 (discussedabove with respect to FIGS. 9 and 13) as the front cover 92 and the backcover 93 come into contact with one another. Additionally oralternatively, each of one or more of the second guide features 134 maybe configured to receive a corresponding first guide feature 126.

In some cases, the second guide features 134 may engage associated firstguide features 126 prior to the latches 122 fully interacting withassociated latch receivers 132 as the front cover 92 and the back cover93 are brought together. In one example of the second guide features134, the second guide features 134 may extend from an interior surfaceof the back cover 93 and may be configured to be received within anencircled opening of the first guide features 126, as best shown inFIGS. 9-11 and 13. However, it is contemplated that the second guidefeature 134 may take on one or more other shapes and/or may beconfigured to receive the first guide features 126 therein. As discussedabove, the guide features may help prevent the sidewall of the frontcover 92 from bowing out when the latches 122 interact with associatedlatch receivers 132.

The back cover 93 may include any number of second guide features 134.In some instances, there may be one (1), two (2), three (3), four (4),six (6), eight (8) second guide features 134 or other number of secondguide features 134. As shown in FIG. 10, the back cover 93 may include asecond guide feature 134 adjacent the perimeter of the back cover 93such that each side edge of the back cover 93 has a second guide feature134 equally spaced between two latch receivers 132.

In some cases, each corner of the interior side of the back cover 93 mayinclude a second guide feature 134 that may or may not take on a similarform as the second guide features 134 that may be positioned along theside edges of the interior side of the back cover 93. In one example, asshown in FIG. 10, the second guide features 134 located in the cornersof the interior side of the back cover 93 may take a different form thanthe second guide features 134 along the side edges of the interior sideof the back cover 93 and may form a corner for receiving the first guidefeatures 126 in the corners on the interior side of the front cover 92.

When the first guide features 126 and the second guide features 134 areomitted from the housing 90, a gap may form between edge 124 of thefront cover 92 and edge 136 of the back cover 93. The gap may form forany of a number of reasons. In one example, the gap may form due to aconfiguration of the latches 122 (e.g., a configuration configured toprevent ghosting artefacts on walls of the front cover 92), bending orstretching of the wall of the front cover 92 or back cover as thelatches 122 engage the latch receivers 132, a thickness of the walls ofthe housing 90, a material of the housing 90, and/or the gap may formfor other reasons. In some cases, the gap may be permanent without thefirst and second guide features.

The first guide features 126 and the second guide features 134 may bepositioned to help prevent or mitigate formation of gaps between thefront cover 92 and the back cover 93. The combination of latchingmechanisms (e.g., the latches 122 and the latch receivers 132) withguide features (e.g., the first guide features 126 and the second guidefeatures 134) may result in a good stiff connection between parts, whilemaintaining a gap free interface even when the sidewalls of the frontcover 92 are fairly thin.

FIG. 14 is a perspective view of the display 96 with the displayflextail 110 (e.g., a flexible circuit). In one example, the displayflextail 110 may be configured to extend from a bottom of the display96, extend around the back light reflector and display spacer assembly104, and connect to a back side of the PWB 102, where the PWB 102 has afront side facing the back light reflector and display spacer assembly104 and a back side facing an opposite direction. When the displayflextail 110 is connected to the PWB 102, the display 96 may beelectrically connected to the PWB 102. The flextail 110 may be aflexible circuit, a ribbon cable, or any other suitable flexiblecircuit.

As shown in FIG. 14, the display flextail 110 may include a temperaturesensor 114, such as a thermistor. The thermistor 114 may be attached tothe flextail 110 in any manner including, but not limited to, bysoldering or other connection technique. The thermistor 114 may be theonly thermistor 114 utilized by the thermostat 82 or one of two or morethermistors used by the thermostat 82 to sense and/or determine ambienttemperature around the thermostat 82. In some cases, the thermistor 114may be electrically connected to the PWB 102 through the displayflextail 110, while in another cases the thermistor 114 may beelectrically connected to the PWB 102 via a different connectionmechanism.

As electronic components of the thermostat 82, such as the touch screen98, the display 96, electrical components on the PWB 102, and/or otherelectrical components, may produce heat as those components operate, ithas been found to be desirable to separate and/or isolate at least onethermistor of the thermostat from such heat producing components. In oneinstance, it may be desirable to place at least one thermistor at alocation within the thermostat 82 (e.g., within housing 90) that may beless influenced by heat of electronic components operating therein.

Illustratively, ambient temperature around a thermostat may bedetermined by utilizing measurements from at least two thermistors,where one thermistor is considered a cold thermistor and anotherthermistor is considered a warmer thermistor. A warmer thermistor may beplaced near electronic components producing heat and a cold thermistormay be spaced from the electronic components producing heat. A processorof a thermostat using at least two thermistors may take measurementsfrom the warmer thermistor and the cold thermistor and determine anambient temperature from a heat flow equation.

It has been determined, relative to other locations within the housing90 of the thermostat 82, that adjacent a bottom of the interior surfaceof the front cover 92 is a location that may be minimally affected byheat exhausted from operating electronic components of the thermostat 82and thus, may be considered an acceptable location to place a coldthermistor. This may be particularly so in the disclosed thermostatwhere the display 96 and/or the PWB 102 do not extend to a base of theinterior surface of the housing 90 (e.g., front cover 92, as seen forexample in FIG. 15).

To facilitate positioning a thermistor 114 adjacent the interior surfaceof the housing 90, the thermistor 114 may be placed on a flextail orother flexible circuit extending from the PWB 102, as such flextails mayextend adjacent to and/or touch a bottom of the housing 90 that isspaced from the PWB 102 and/or other heat producing components of thethermostat 82. Although the thermistor 114 is discussed as being placedon the display flextail 110, the thermistor 114 may be placed on anyflexible circuit including, but not limited to, the screen flextail 108,the display flextail 110, and its own flexible circuit.

As shown in FIG. 15, the thermistor 114 may be mounted on the displayflextail 110 at a location that abuts or is adjacent an interior surfaceof the front cover 92 below the display 96, the PWB 102, and the backlight reflector and display spacer assembly 104. In one example, thethermistor may face the interior surface of the front cover 92 when thedisplay flextail 110 is connected to the PWB 102. Further, utilizationof the display flextail 110 may be advantageous during manufacturingbecause less material is required and one fewer component for connectionto the PWB 102 may be needed.

To facilitate proper and repeatable placement of the thermistor 114, thefront cover 92 may include one or more thermistor spacing ribs 116. Thethermistor spacing ribs 116 of the front cover 92 may help ensure thatthe thermistor 114 is positioned at a same location and a same distancefrom the front cover 92 by contacting the display flextail 110 as itwraps around the PWB 102 to ensure proper bending and/or deformation ofthe display flextail. It may be desirable to ensure the thermistor 114is consistently located within the housing 90 during manufacturing sothat equations used to determine an ambient temperature around thethermostat accurately determine a temperature at the thermistor 114.

Although not shown, the thermistor 114 on the display flextail 110 maybe isolated from electronic components producing heat by an additionalmaterial. Illustratively, a heat conducting material may be placedbetween the thermistor 114 and a wall of the housing 90. In one example,the heat conducting material may be a rubber and/or a foam basedmaterial. Such material may be in a paste or other form and may beapplied to the front cover 92 with a pocket formed therein that may beconfigured to receive the thermistor 114.

Those skilled in the art will recognize that the present disclosure maybe manifested in a variety of forms other than the specific embodimentsdescribed and contemplated herein. Accordingly, departure in form anddetail may be made without departing from the scope and spirit of thepresent disclosure as described in the appended claims.

What is claimed is:
 1. A thermostat, comprising: a display assembly; aprinted wiring board; a flextail extending from the display assembly tothe printed wiring board; and a first temperature sensor mounted on theflextail and electrically connected to the printed wiring board.
 2. Thethermostat of claim 1, further comprising a housing for housing thedisplay assembly, the printed wiring board, the flextail, and the firsttemperature sensor.
 3. The thermostat of claim 2, wherein the firsttemperature sensor is mounted on the flextail so as to be positionedadjacent an interior surface of the housing.
 4. The thermostat of claim3, wherein the flextail wraps around a bottom edge of the printed wiringboard, and the first temperature sensor is mounted to a portion of theflextail that wraps around the bottom edge of the printed wiring board.5. The thermostat of claim 3, wherein the first temperature sensor ispositioned adjacent a bottom side of the housing.
 6. The thermostat ofclaim 5, wherein the display assembly is spaced from the bottom side ofthe housing.
 7. The thermostat of claim 2, wherein an interior surfaceof the housing includes one or more ribs that are configured to engageand align the flextail such that the first temperature sensor ispositioned at a desired location within the housing.
 8. The thermostatof claim 2, wherein the housing has a first cover and a second coverconfigured to engage the first cover.
 9. The thermostat of claim 8,wherein the first cover has one or more ribs that are configured toengage and align the flextail.
 10. The thermostat of claim 8, whereinthe first cover has an opening configured to allow a user to view thedisplay assembly.
 11. The thermostat of claim 2, further comprising aheat conductive material between the first temperature sensor and aninterior surface of the housing.
 12. The thermostat of claim 2, furthercomprising: a second temperature sensor; and wherein the firsttemperature sensor is spaced from the second temperature sensor.
 13. Thethermostat of claim 12, further comprising: a processor in communicationwith the first temperature sensor and the second temperature sensor; andwherein the processor is configured to determine an ambient temperatureoutside of the housing, based on measurements from both the firsttemperature sensor and the second temperature sensor.
 14. An HVACcontroller, comprising: control circuitry; a flexible circuitoperatively coupled to the control circuitry; and a temperature sensorsecured to the flexible circuit and operatively coupled to the controlcircuitry via the flexible circuit; and a display operatively coupled tothe control circuitry.
 15. The HVAC controller of claim 14, wherein: theflexible circuit has a first end connected to the display and a secondend opposite of the first end operatively coupled to the controlcircuitry; and the temperature sensor is spaced from the first end andthe second end.
 16. The HVAC controller of claim 14, further comprising:a printed wiring board incorporating at least some of the controlcircuitry; and wherein the printed wiring board is configured toelectrically connect to the display via the flexible circuit.
 17. TheHVAC controller of claim 16, wherein the display is positioned adjacenta first side of the printed wiring board and the flexible circuitconnects to a second opposing side of the printed wiring board.
 18. TheHVAC controller of claim 16, wherein: the flexible circuit has a firstside and a second side; the temperature sensor extends from the firstside and faces away from the printed wiring board; and the second sidefaces the printed wiring board.
 19. A device comprising: a flexiblecircuit; a temperature sensor secured to the flexible circuit; a printedwiring board electrically connected to the flexible circuit; and ahousing at least partially housing the flexible circuit, the temperaturesensor, and the printed wiring board.
 20. The device of claim 19,wherein the temperature sensor is spaced from the printed wiring boardand faces an interior surface of the housing.